Structure and Catalytic Properties of a Cu2+-Containing Hydrogel of Zirconium Dioxide

The distribution of Cu²⁺ ions in ZrO₂ and sulfated ZrO₂ hydrogel phases was studied by EPR spectroscopy and voltammetry. The formation of the following three types of copper structures was observed: mononuclear Cu²⁺ complexes (A), magnetic associates (B), and Cu²⁺ compounds (C) that gave no EPR signals under the conditions used in the spectroscopic measurements. The specific catalytic activity of various Cu²⁺ compounds in the liquid-phase reaction of 2,3,5-trimethyl-1,4-hydroquinone oxidation was determined. The copper complexes C were found to exhibit the highest catalytic activity.     

Oxidation of 2,3,6-trimethylphenol on titanium dioxide xerogel by hydrogen peroxide in the absence of an organic solvent

Fundamental aspects of the synthesis of 2,3,5-trimethylbenzoquinone by oxidation of 2,3,6-trimethylphenol adsorbed on the surface of a titanium dioxide xerogel and on TiO₂ modified with powdered cellulose with hydrogen peroxide without any organic solvent involved in the process were studied.     

Synthesis of Cu(II)-containing TiO2-SiO2 binary xerogels by hydrolysis of a mixture of tetrabutoxytitanium, tetraethoxysilane, and copper(II) chloride in a water-ammonia atmosphere

A Cu(II)-containing binary xerogel TiO₂-SiO₂ was synthesized by joint hydrolysis of tetrabutoxytitanium, teraethoxysilane and copper(II) chloride dissolved in their mixture. The synthesis was performed in a vapor of 10% aqueous ammonia under static conditions. EPR spectroscopy was used to examine the state of Cu(II) in the xerogel matrix. Data on specific features of the behavior of saccharose within xerogel pores under heating were obtained. The catalytic activity of the xerogel was tested by the kinetic method on model reactions of hydrogen peroxide decomposition and oxidative dehydrogenation of trimethylhydroquinone.     

Three-step synthesis of Pd0/TiO2

Russian Chemical Bulletin - A simplifi ed procedure for the synthesis of Pd0/TiO2 xerogel has been developed, which includes the following steps: hydrolysis of tetrabutoxytitanium from its mixture...     

Synthesis of porous zirconium and titanium dioxides by hydrolysis of tetrabutoxyzirconium (tetrabutoxytitanium) with atmospheric moisture in the absence of acid-base catalysts with the use of cellulose and activated charcoal as matrices

Synthesis of porous zirconium and titanium dioxides was accomplished by a procedure that includes impregnation of cellulose and activated charcoal matrices with tetrabutoxyzirconium (tetrabutoxytitanium) solutions, hydrolysis of the precursors with atmospheric moisture at 25°C, burning the matrix, and incineration of xerogels at 850°C. Relationship between precursor solution concentration at impregnation stage, matrix type, and physicochemical properties of prepared materials was established.     

Synthesis of TiO2-SiO2 xerogels via the hydrolysis of a tetrabutoxytitanium-tetraethoxysilane mixture in aqueous ammonia and hydrochloric acid atmospheres

TiO₂-SiO₂ xerogels have been synthesized by the hydrolysis of tetrabutoxytitanium-tetraethoxysilane mixtures in a 10% aqueous ammonia vapor and concentrated hydrochloric acid vapor atmospheres under static conditions. The dependence of the physical and chemical properties of the xerogels on the synthetic conditions has been investigated.     

Behavior of nanosized tungsten oxide bronzes produced by high-temperature electrolysis in model processes of desulfurization of petroleum products

Tungsten oxide bronzes were produced by an original method of high-temperature electrochemical deposition. Their catalytic properties in a model process of desulfurization of petroleum products-benzothiophene peroxidation were studied. The effect of the particle size on the catalytic and catalase activity of samples was shown.     

Medium acidity and catalytic properties of composite materials based on silica and titania and powder cellulose in the presence of Cu<Superscript>2+</Superscript> ions

Composite materials (CMs) were synthesized from silica and titania xerogels. The influence of the charged state of the CM surface on complexation with Cu²⁺ ions and the catalytic activity of the obtained samples in model oxidative dehydrogenation of trimethylhydroquinone with air oxygen was analyzed. Using powder cellulose in the synthesis of CMs increased the specific surface of inorganic dioxides and lowered the negative electric potential of the CM surface. This caused a redistribution of the ratio between different types of copper structures formed in the samples during the copper sorption and led to the catalytic activity of the CMs.     

A carbon-silica composite material based on powdered cellulose: Synthesis and properties

A procedure was developed for preparing a carbon-silica composite by thermolysis of powdered cellulose in the presence of tetraethoxysilane. The resulting composite was studied in model processes of trimethylhydroquinone oxidation and hydrogen peroxide decomposition.     

EPR study of copper(II) complexes in the matrix of titania gel modified with powder cellulose

The character of the copper(II) distribution over the surface of titania gel modified with powder cellulose has been studied by EPR. Three types of copper(II) compounds have been identified: mononuclear complexes, magnetic associates, and copper(II) compounds that do not give rise to an observable EPR spectrum at the used frequency and temperature. The modification of titania gel has been shown to have an effect on the relative contents of these compounds.